Welcome to the forums.
If you are going to be in the delta, you may opt for one of the boatyard in the delta as they are quite a bit cheaper than svendsons.
You should post a picture of your mast. Your 'mast' plan sound very aggressive. I am unsure if you can safely lift anything from a 5 ft mast unless it is properly stayed and built very heavy. How heavy is the dink you are trying to lift up there?
You may consider a pipe davit as others have suggested as they can handle much more weight safely, they will reach to the stern of your boat, and have power winches built into them. They will also fold up nicely out of the way.
Although I have one, I dont find stern thrusters to be very useful. BUT If you want a good stern thruster, try Welcome to Dickson Thruster
. They are out of Stockton and they can sell you the kit or install it for you. They are not overly expensive and since they are hydraulic , you can run it all day without overheating.
What marina are you at? We are currently at Bruno's in Isleton.